Inhibition of insulin, glucose-dependant insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) secretion by octreotide has no effect on post-heparin plasma lipoprotein lipase activity

This study examines the immediate effect of modulating postprandial insulin and insulinotropic hormone (glucose-dependent insulinotropic polypeptide, GIP; glucagon-like peptide-1, GLP-1) secretion on the activation of lipoprotein lipase (LPL) in six lean and six obese age-matched women. Subjects were given, on two separate occasions, 340 kcal of carbohydrate alone or combined with an IV infusion of octreotide, (100 mu g infusion from 30 min before the meal for 150 min). Post-heparin LPL activity (10,000 U) was measured on each occasion 120 minutes post-carbohydrate. Following oral carbohydrate postprandial plasma insulin levels were significantly higher in obese subjects than in lean (p<0.01), Glucose tolerance was slightly impaired in obese subjects. Insulin, GIP and GLP-1 secretion post-carbohydrate was markedly reduced by octreotide in lean and obese subjects. LPL activity was similar in the two groups after carbohydrate administration and was unaffected by octreotide. Inhibition of postprandial insulin, GIP and GLP-1 secretion acutely did not reduce post-heparin LPL activity either in lean or obese subjects.